src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1993-1994, 2001-2013 Free Software Foundation, Inc.
   3
   4 Author: Howard Gayle
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software: you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation, either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22
  23 #include "lisp.h"
  24 #include "character.h"
  25 #include "buffer.h"
  26
  27 static Lisp_Object Qcase_table_p, Qcase_table;
  28 Lisp_Object Vascii_downcase_table;
  29 static Lisp_Object Vascii_upcase_table;
  30 Lisp_Object Vascii_canon_table;
  31 static Lisp_Object Vascii_eqv_table;
  32
  33 static void set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt);
  34 static void set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
  35 static void shuffle (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
  36
  37 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
  38        doc: /* Return t if OBJECT is a case table.
  39 See `set-case-table' for more information on these data structures.  */)
  40   (Lisp_Object object)
  41 {
  42   Lisp_Object up, canon, eqv;
  43
  44   if (! CHAR_TABLE_P (object))
  45     return Qnil;
  46   if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
  47     return Qnil;
  48
  49   up = XCHAR_TABLE (object)->extras[0];
  50   canon = XCHAR_TABLE (object)->extras[1];
  51   eqv = XCHAR_TABLE (object)->extras[2];
  52
  53   return ((NILP (up) || CHAR_TABLE_P (up))
  54           && ((NILP (canon) && NILP (eqv))
  55               || (CHAR_TABLE_P (canon)
  56                   && (NILP (eqv) || CHAR_TABLE_P (eqv))))
  57           ? Qt : Qnil);
  58 }
  59
  60 static Lisp_Object
  61 check_case_table (Lisp_Object obj)
  62 {
  63   CHECK_TYPE (!NILP (Fcase_table_p (obj)), Qcase_table_p, obj);
  64   return (obj);
  65 }
  66
  67 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  68        doc: /* Return the case table of the current buffer.  */)
  69   (void)
  70 {
  71   return BVAR (current_buffer, downcase_table);
  72 }
  73
  74 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
  75        doc: /* Return the standard case table.
  76 This is the one used for new buffers.  */)
  77   (void)
  78 {
  79   return Vascii_downcase_table;
  80 }
  81
  82 static Lisp_Object set_case_table (Lisp_Object, bool);
  83
  84 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  85        doc: /* Select a new case table for the current buffer.
  86 A case table is a char-table which maps characters
  87 to their lower-case equivalents.  It also has three \"extra\" slots
  88 which may be additional char-tables or nil.
  89 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
  90 UPCASE maps each non-upper-case character to its upper-case equivalent.
  91  (The value in UPCASE for an upper-case character is never used.)
  92  If lower and upper case characters are in 1-1 correspondence,
  93  you may use nil and the upcase table will be deduced from DOWNCASE.
  94 CANONICALIZE maps each character to a canonical equivalent;
  95  any two characters that are related by case-conversion have the same
  96  canonical equivalent character; it may be nil, in which case it is
  97  deduced from DOWNCASE and UPCASE.
  98 EQUIVALENCES is a map that cyclically permutes each equivalence class
  99  (of characters with the same canonical equivalent); it may be nil,
 100  in which case it is deduced from CANONICALIZE.  */)
 101   (Lisp_Object table)
 102 {
 103   return set_case_table (table, 0);
 104 }
 105
 106 DEFUN ("set-standard-case-table", Fset_standard_case_table,
 107        Sset_standard_case_table, 1, 1, 0,
 108        doc: /* Select a new standard case table for new buffers.
 109 See `set-case-table' for more info on case tables.  */)
 110   (Lisp_Object table)
 111 {
 112   return set_case_table (table, 1);
 113 }
 114
 115 static Lisp_Object
 116 set_case_table (Lisp_Object table, bool standard)
 117 {
 118   Lisp_Object up, canon, eqv;
 119
 120   check_case_table (table);
 121
 122   up = XCHAR_TABLE (table)->extras[0];
 123   canon = XCHAR_TABLE (table)->extras[1];
 124   eqv = XCHAR_TABLE (table)->extras[2];
 125
 126   if (NILP (up))
 127     {
 128       up = Fmake_char_table (Qcase_table, Qnil);
 129       map_char_table (set_identity, Qnil, table, up);
 130       map_char_table (shuffle, Qnil, table, up);
 131       set_char_table_extras (table, 0, up);
 132     }
 133
 134   if (NILP (canon))
 135     {
 136       canon = Fmake_char_table (Qcase_table, Qnil);
 137       set_char_table_extras (table, 1, canon);
 138       map_char_table (set_canon, Qnil, table, table);
 139     }
 140
 141   if (NILP (eqv))
 142     {
 143       eqv = Fmake_char_table (Qcase_table, Qnil);
 144       map_char_table (set_identity, Qnil, canon, eqv);
 145       map_char_table (shuffle, Qnil, canon, eqv);
 146       set_char_table_extras (table, 2, eqv);
 147     }
 148
 149   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 150   set_char_table_extras (canon, 2, eqv);
 151
 152   if (standard)
 153     {
 154       Vascii_downcase_table = table;
 155       Vascii_upcase_table = up;
 156       Vascii_canon_table = canon;
 157       Vascii_eqv_table = eqv;
 158     }
 159   else
 160     {
 161       bset_downcase_table (current_buffer, table);
 162       bset_upcase_table (current_buffer, up);
 163       bset_case_canon_table (current_buffer, canon);
 164       bset_case_eqv_table (current_buffer, eqv);
 165     }
 166
 167   return table;
 168 }
 169 \f
 170 /* The following functions are called in map_char_table.  */
 171
 172 /* Set CANON char-table element for characters in RANGE to a
 173    translated ELT by UP and DOWN char-tables.  This is done only when
 174    ELT is a character.  The char-tables CANON, UP, and DOWN are in
 175    CASE_TABLE.  */
 176
 177 static void
 178 set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt)
 179 {
 180   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 181   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 182
 183   if (NATNUMP (elt))
 184     Fset_char_table_range (canon, range, Faref (case_table, Faref (up, elt)));
 185 }
 186
 187 /* Set elements of char-table TABLE for C to C itself.  C may be a
 188    cons specifying a character range.  In that case, set characters in
 189    that range to themselves.  This is done only when ELT is a
 190    character.  This is called in map_char_table.  */
 191
 192 static void
 193 set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt)
 194 {
 195   if (NATNUMP (elt))
 196     {
 197       int from, to;
 198
 199       if (CONSP (c))
 200         {
 201           from = XINT (XCAR (c));
 202           to = XINT (XCDR (c));
 203         }
 204       else
 205         from = to = XINT (c);
 206
 207       to++;
 208       for (; from < to; from++)
 209         CHAR_TABLE_SET (table, from, make_number (from));
 210     }
 211 }
 212
 213 /* Permute the elements of TABLE (which is initially an identity
 214    mapping) so that it has one cycle for each equivalence class
 215    induced by the translation table on which map_char_table is
 216    operated.  */
 217
 218 static void
 219 shuffle (Lisp_Object table, Lisp_Object c, Lisp_Object elt)
 220 {
 221   if (NATNUMP (elt))
 222     {
 223       int from, to;
 224
 225       if (CONSP (c))
 226         {
 227           from = XINT (XCAR (c));
 228           to = XINT (XCDR (c));
 229         }
 230       else
 231         from = to = XINT (c);
 232
 233       to++;
 234       for (; from < to; from++)
 235         {
 236           Lisp_Object tem = Faref (table, elt);
 237           Faset (table, elt, make_number (from));
 238           Faset (table, make_number (from), tem);
 239         }
 240     }
 241 }
 242 \f
 243 void
 244 init_casetab_once (void)
 245 {
 246   register int i;
 247   Lisp_Object down, up, eqv;
 248
 249   DEFSYM (Qcase_table, "case-table");
 250   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 251
 252   down = Fmake_char_table (Qcase_table, Qnil);
 253   Vascii_downcase_table = down;
 254   set_char_table_purpose (down, Qcase_table);
 255
 256   for (i = 0; i < 128; i++)
 257     {
 258       int c = (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i;
 259       CHAR_TABLE_SET (down, i, make_number (c));
 260     }
 261
 262   set_char_table_extras (down, 1, Fcopy_sequence (down));
 263
 264   up = Fmake_char_table (Qcase_table, Qnil);
 265   set_char_table_extras (down, 0, up);
 266
 267   for (i = 0; i < 128; i++)
 268     {
 269       int c = (i >= 'a' && i <= 'z') ? i + ('A' - 'a') : i;
 270       CHAR_TABLE_SET (up, i, make_number (c));
 271     }
 272
 273   eqv = Fmake_char_table (Qcase_table, Qnil);
 274
 275    for (i = 0; i < 128; i++)
 276      {
 277       int c = ((i >= 'A' && i <= 'Z') ? i + ('a' - 'A')
 278                : ((i >= 'a' && i <= 'z') ? i + ('A' - 'a')
 279                   : i));
 280       CHAR_TABLE_SET (eqv, i, make_number (c));
 281     }
 282
 283   set_char_table_extras (down, 2, eqv);
 284
 285   /* Fill in what isn't filled in.  */
 286   set_case_table (down, 1);
 287 }
 288
 289 void
 290 syms_of_casetab (void)
 291 {
 292   DEFSYM (Qcase_table_p, "case-table-p");
 293
 294   staticpro (&Vascii_canon_table);
 295   staticpro (&Vascii_downcase_table);
 296   staticpro (&Vascii_eqv_table);
 297   staticpro (&Vascii_upcase_table);
 298
 299   defsubr (&Scase_table_p);
 300   defsubr (&Scurrent_case_table);
 301   defsubr (&Sstandard_case_table);
 302   defsubr (&Sset_case_table);
 303   defsubr (&Sset_standard_case_table);
 304 }